Fix: Preserve Whoosh date range swapping in Tantviy (#12866)

src/documents/search/_query.py

@@ -390,8 +390,13 @@ def _rewrite_year_range(query: str) -> str:
 
     def _sub(m: regex.Match[str]) -> str:
         field = m.group("field")
-        lo = datetime(int(m.group("y1")), 1, 1, tzinfo=UTC)
-        hi = datetime(int(m.group("y2")) + 1, 1, 1, tzinfo=UTC)
+        y1, y2 = int(m.group("y1")), int(m.group("y2"))
+        # Whoosh swaps a reversed range when both years are explicit
+        # (whoosh.util.times.timespan.disambiguated); match that so a backwards
+        # range spans the intended years instead of matching nothing.
+        lo_year, hi_year = min(y1, y2), max(y1, y2)
+        lo = datetime(lo_year, 1, 1, tzinfo=UTC)
+        hi = datetime(hi_year + 1, 1, 1, tzinfo=UTC)
         return f"{field}:[{_fmt(lo)} TO {_fmt(hi)}]"
 
     try:

src/documents/tests/search/test_query.py

@@ -519,6 +519,14 @@ class TestYearRangeRewriting:
         assert lo == expected_lo
         assert hi == expected_hi
 
+    def test_reversed_year_range_is_swapped(self) -> None:
+        # A reversed range must not yield lo > hi, which Tantivy treats as an
+        # empty range (silently zero results). The bounds are swapped instead.
+        result = rewrite_natural_date_keywords("created:[2025 TO 2020]", UTC)
+        lo, hi = _range(result, "created")
+        assert lo == "2020-01-01T00:00:00Z"
+        assert hi == "2026-01-01T00:00:00Z"
+
     def test_year_range_in_complex_boolean_query(self) -> None:
         query = "tag:steuer AND (title:2020 OR (NOT title:2019 AND NOT title:2018 AND created:[2020 TO 2020]))"
         result = rewrite_natural_date_keywords(query, UTC)